Coated glass sheets often are easily damaged. For example, coated glass sheets sometimes are less durable while in the annealed state (e.g., prior to tempering). Indeed, glass sheets often are highly susceptible to damage during cutting, loading/unloading from glass racks or pallets, shipment, edge seaming, post-washing handling, etc. The coated side of the coated sheets are the most vulnerable to damage (e.g., scratching and the like) in this regard.
For example, coated sheets are often scratched due to one or more of rubbing up against other sheets or the like during shipment, pliers used by glass handlers, abrasion caused by gloves worn by glass handlers, brushes used during the washing, and other types of rubbing/abrasion. Additionally, corrosion is also a significant cause of damage and often is caused by high humidity conditions, acid rain, and/or other materials which tend to collect on the coated articles during transport, storage and/or handling.
While the aforesaid types of damage often occur prior to heat treatment (e.g., tempering), the tempering of the coated sheets typically magnifies such damage. For example, a minor bit of corrosion which was caused pre-tempering can lead to a significant blemish upon heat treatment which causes the coated sheet to be scrapped. The same is true for scratch damage because scratches in a coating allow oxidation to occur deep within the coating and possibly at the silver layer(s) during heat treatment (e.g., tempering) since heat treatment is typically conducted in an oxygen-inclusive atmosphere. Thus, the damage to a coated article often tends to be worse following heat treatment. Accordingly, it can be seen that yields appreciably suffer due to pre-HT damage that tends to occur to coated glass sheets.
To better protect coated glass sheets in various processing stages, temporary protective coatings have been developed. See, for example, U.S. Publication Nos. 2005/0210921 and 2008/0302462, and U.S. application Ser. Nos. 12/222,071 and 12/222,459, the entire contents of each of which are hereby incorporated herein by reference. The temporary protective coatings may be applied in solid or liquid forms and are designed such that they can be easily removed, typically by peeling.
Glass coating companies often require coating edge deletion for many of their products, for example, to help ensure proper adhesion of materials such as sealants to their glass surfaces. In this regard, edge deletion tables are known. See, for example, U.S. Pat. Nos. 4,716,686; 5,713,986; 5,934,982; 6,971,948; 6,988,938; 7,125,462; and 7,140,953, each of which is hereby incorporated herein in its entirety. A series of casters provided to the table allow for smooth movement of glass across the surface of the table. Grinding wheels of various widths may be used in connection with shields to help reduce the scattering of debris and for safety purposes. Passing the glass substantially consistently under the deletion head efficiently “deletes” the coating from the glass so that it can be used, for example, with sealants in intermediate or finished products. Wider or narrower grinding wheels may be used to delete more or less coating from the glass surface.
It will be appreciated that it would be advantageous to perform edge deletion when a temporary protective coating is on a coated article, e.g., without having to remove the temporary protective coating from the area where edge deletion is to be performed. Unfortunately, however, this is not possible using current apparatuses. Indeed, current apparatuses are designed only to edge delete the coating disposed on the substrate. Thus, the temporary protective coating needs to be at least partially removed prior to edge deletion. However, removing too much of the temporary protective coating exposes the underlying coated substrate, whereas removing too little will hamper, and often completely prevent, proper edge deletion. In either case, the manual or even machine removal of the temporary protective coating introduces additional process steps and/or risks damage to the articles and/or machinery involved, thus injecting delays into the process, reducing yield, and increasing costs.
Simply attempting to perform edge deletion with the temporary protective coating on the coated article does not work, as the edge deletion table is not designed to work in this way. Indeed, sometimes the temporary protective coating is removed and only part of the coating disposed on the substrate is removed, whereas other times the coating may be marred or otherwise damaged but not sufficiently deleted. The temporary protective coating may wrinkle or otherwise become deformed or damaged adjacent the portion where edge deletion is supposed to occur. A significant amount of debris also is typically produced when edge deletion with the temporary protective coating on the coated article is attempted, and this debris often will contaminate the room, remain on or otherwise negatively impact the substrate, create problems for the edge deletion unit (such as, for example, clogging, etc.), and/or lead to other drawbacks.
Thus, it will be appreciated that there is a need in the art for techniques for edge deleting coatings provided to coated articles when temporary protective coatings are applied thereto, e.g., at a common area of interest. It also will be appreciated that, as a part of such techniques, it would be advantageous to control the debris produced when edge deletion is performed on a coated article having a temporary protective coatings applied thereto.
In certain example embodiments of this invention, an apparatus is provided. The apparatus of certain example embodiments comprises (1) a substantially horizontally oriented edge deletion table; (2) an edge deletion unit suspended above the edge deletion table, with the edge deletion unit comprising a grinding wheel and a nozzle located proximate to the grinding wheel; (3) an aspirator located adjacent to the apparatus; and (4) tubing connecting the aspirator to the nozzle of the edge deletion unit. The grinding wheel of the edge deletion unit and the aspirator are arranged so as to cooperate in allowing the apparatus to edge delete a coated article and remove a temporary protective coating provided to the coated article from a common area of interest.
In certain example embodiments of this invention, an edge deletion apparatus is provided. An edge deletion table is provided in connection therewith. An edge deletion unit is suspended above the edge deletion table, with the edge deletion unit comprising (1) a grinding wheel, (2) a nozzle located proximate to the grinding wheel, and (3) a shield provided generally around the sides of the grinding wheel such that at least a bottom portion of the grinding wheel protrudes downwardly from the shield. An aspirator is located adjacent to the apparatus, with the aspirator being stationary during operation. Tubing connects the aspirator to the nozzle of the edge deletion unit. The grinding wheel of the edge deletion unit and the aspirator are arranged so as to cooperate in allowing the apparatus to edge delete a coating on a coated article and remove a temporary protective coating provided to the coated article from a common area of interest. The aspirator is configured to capture substantially all debris created by the grinding wheel when a coating on a coated article is edge deleted and a temporary protective coating provided thereto is removed.
In certain example embodiments of this invention, a method of edge deleting a coating supported by a substrate having a temporary protective coating provided thereon is provided. There is provided an apparatus comprising (1) a substantially horizontally oriented edge deletion table, (2) an edge deletion unit suspended above the edge deletion table, the edge deletion unit comprising a grinding wheel and a nozzle located proximate to the grinding wheel, (3) an aspirator located adjacent to the apparatus, and (4) tubing connecting the aspirator to the nozzle of the edge deletion unit. The substrate supporting both the coating and the temporary protective coating is provided to the apparatus such that it advances down the edge deletion table. The grinding wheel of the edge deletion unit and the aspirator are allowed to cooperate to perform edge deletion on the coating provided to the coated article and remove the temporary protective coating provided thereto, from a common area of interest. Via the aspirator, substantially all debris created by the grinding wheel when the coating provided to the coated article is edge deleted and the temporary protective coating provided thereto is removed is captured.
In general, methods for edge deleting a coating supported by a substrate having a temporary protective coating provided thereon may take advantage of any of the apparatuses disclosed herein in certain example embodiments.
The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.